Amino acrylate esters



United States Patent 3,094,554 AMINO ACRYLATE ESTERS Jack Dickstein,Huntingdon Valley, Pa., and Michael Bodnar, Dover, and Rose-MarieHoegerle, Linden, NJ., assignors to The Borden Company, New York, N.Y.,a corporation of New Jersey No Drawing. Filed Feb. 20, 1961, Ser. No.90,178 6 Claims. (Cl. 260-482) This invention relates toZ-aminoalkylacrylate esters and the process of making them.

The formula for our esters may be written as iIJHI (RhN-IV-C-C 0 0 R" inwhich R is a monovalent component selected from the 'group consisting ofhydrogen and C-C alkyls, R is a bivalent hydrocarbon 'group having 1-3carbon atoms, and R" is a monovalent radical selected from the groupconsisting of C C alkyls, allyl and phenyl.

Examples of compounds that illustrate the invention and meanings of theseveral R in order, from left to right are the following: EthylZ-aminomethylacrylate F NHz-QHr-O O O Cal-Ir Tri-(ethyl2-methylenepropionate) amine CH; N(OH'P! Q 0 0023s): Ethyl 2 N,N-dimethyla =mi 1 i opg e t hyl) -acryl ate a GE;

(CH3)IN-0Hgl-OOOC;H5 Ethyl 2-(N,N-diethylaminomethyl)-acrylate CH:(CQH5)INCH2HT-O O 0 01H; Ethyl 2-(N,N,N-triethylammoniummethyl)acrylatebromide Br CIHI O' HgfliF-GHr lJ COOGQHt '7 The products of thisinvention are'useful as polyelectrolytes for controlling the viscosityof aqueous solutions to which they are added. Efiectiveness for thispurpose requires a high content of the hydrocarbon moiety which issupplied by the various Rs in the formula shown. Also the products areuseful as surface active agents as in detergents, particularly when'theseveral Rs have carbon atoms in numbers that are relatively high withinthe ranges recited for the various Rs. The polyelectrolytes and thesurfiace active agents are used in the form of salts such as made byreaction of compounds of the formula shown with a monoalkyl bromide orthe like, as to form a quaternary ammonium compound and develop cationicproperties in the product.

The invention comprises the Z-aminoalkylacrylate esters of the formulaabove and their salts.

The invention comprises also the process of making the compounds of kinddescribed by action of ammonia or an amine containing the R on the2-bromoalkylacrylate ester providing the R and R" groups that are toappear in the finished product.

The Z-hromoalkylacrylate ester of kind described and of the formula isreacted in the cold with an excess of ammonia or an amine in alcohol orlike solvent. Unless other alkali is 3,094,554 Patented June 18, 1963added, the ammonia or the amine is used in amount to correspond at leastto 2 moles for 1 mole of the broomalkylacrylate used. The reactioninvolves one bromine containing group of the ester, thus R'Br In thefirst of these reactions R' is H.

When theallraliuity has decreased to a substantially constantlevel'or'when the bromide ion content of the reaction mixture has risento a substantially constant level, either of which condition isdeterminable by analysis, then the reaction is considered complete. Atthis time the desired aminoalkylacrylate ester will be in the form of aprecipitate. A small amount of water is added to promote solution of anyammonium or alkylammonium bromide that may also be undissolved and theaqueous solution so formed is filtered away from theZ-aminoalkylacrylate estcr'that remains. k.

This process illustrated more specifically by the several examples laterherein which also purification steps for separating the esters so obta.from foreign materials. Thus the Z-aminoalkylacrylate ester may bedissolved in water containing hydrochloric or other acid in amount toconvert the amino group of the ester to a salt, the resulting saltsolution filtered from any material remaining undissolved by the acidsolution, and the illtrate then neutralized with an aqueous solution ofca1- cium carbonate or other alkali which destroys the salt andprecipitatcsthe 2-aminoalkylacrylate esterfin nonsalt form, i.e., thehydroxide form. This product isthen extracted by other, the etherextract separated by'diflen ence of specifio'gravity from the aqueousphase, and the ether distilled f As the alkali which combines with thehydrogen bromide, formedas ahyproduct in the replacement of bro mine bythe .NLR'); group, we use the second mole of the amine or 'onium. Tospare a part orall of the second mole, ever, we may introduce anequivalent proportion'of "in-organic water sol'fileealk'ali as, forexample, sodiuirfipotasslum or lithium carbonate.

The tcmperature of the reaction mixture may be raised to accelerate thereplacement of the broom group. This rise will be automatic unlessextreme cooling is used since the reaction is exothermic. We find noadvantage in the use of elevated temperatures that ofisets thedisadvantages in their use and prefer to work'ig the cold, as at about20 to 20" C.

As the solvent in which the bromo compound and the amine or ammonia arereacted we find anhydrous ethanol to be satisfactory as well aseconomical. In place of it we may use any other liquid that is a solventfor the reactants but a precipitant for the resulting amino compound.

Examples of such other solvents that we can use are methanol,isopropanol, dioxane, chloroform, and carbon tetrachloride.

The amount of solvent used is variable. An amount sufilcient to maintainin solution at the start the bromoalkylacrylate ester and the ammonia orthe amine used is convenient and beneficial.

The bromo-substituted esters which serve as intermediates in oursynthesis are made in any conventional manher. A satisfactory method isthat illustratgeas follows:

To prepare ethyl Z-bromomethylacrylate, for instance, 20 g. sodium sandwas made in xylene, washed with tetra- 3 hydrofuran and then coveredwith 230 g. tetrahydrofuran. This was then mixed and reacted withstirring with 200 g. ethylene glycol. After the vigorous reaction hadceased, the resulting solution was maintained at reflux temperature,until all sodium had completely disappeared and reacted with theethylene glycol.

Two phases were formed: a lower, brown ethylene glycol phase containingthe sodium ethylene glycoxide and an upper one consisting mainly oftetrahydrofuran. Both layers were slowly added to a stirred solution of196 g. ethyl 3,3-dibromoisobutyrate in 300 g. tetrahydrofuran, at such arate that the temperature was maintained at 35 38 C. The stirring wascontinued for an additional 1.5 hrs. at room temperature. Then, thereaction mixture was poured into 100 g. ice-cooled water and the organicmaterial extracted with methylene chloride. The combined organicsolutions were dried, filtered, and evaporated under reduced pressure togive an oily residue which upon further distillation yielded a colorlessliquid (105.5 g., 77%), B.P. 61-63" (3.6 mm.), n 1.4755. The formula forthis product is:

Other bromoalkylacrylates are prepared in like manner, i.e., by thesubstitution of ethyl 3,3-dibromoisobutyrate by an equimolar proportionof the dibromo compound containing the alkyl and acid group that are toappear in the ester.

The invention will be further illustrated by description in connectionwith the following examples. Unless specifically stated to the contrary,the dryings were effected over anhydrous magnesium sulfate andproportions, here and elsewhere herein, are expressed as parts byweight.

Example 1-Ethyl 2-(N,N-Dimethylaminoethyl)acrylate 137.5 ml. of a 1.45 Nsolution of dimethylamine in methanol was added to 91.3 g. ethyl2-bromomethyl- *acrylate dissolved in 50 ml. methanol with rapidstirring at a temperature of 15 C. A colorless precipitate separated,after which the mixture was stirred at room temperature for anadditional 0.5 hr. and then stored overnight in the refrigerator. Themixture was acidified with an ether solution of hydrochloric acid to pHabout 5-6 and the solvents evaporated in vacuo. The residue wasdissolved in ice water, mixed with potassium carbonate in amount to givepH 8 and the alkalized product extracted with ether. The combined etherextracts were dried and then evaporated, to leave an oil. Vacuumdistillation gave a colorless oil with strong basic properties: B.P. 75C. (12 mm.), 11, 1.4375, 612 0919.

Analysis.Percent, calculated for C H NO C, 61.16; H, 9.62; N, 8.92.Found: C, 61.06; H, 9.64; N, 8.80.

Infrared absorption spectrum: 1640, 950, 815- shows The picrate preparedin ether and recrystallized melted at 79 C.

AnaIysis.-Calculated for C H N O C, 43.52; H, 4.70; N, 14.50. Found: C,43.51; H, 4.76; N, 14.70.

The hydrochloride was prepared in ethanol with a solution ofhydrochloric acid in ether. It gave colorless, very hygroscopic platesof MP. 93 C.

While the picrate and the hydrochloride were prepared as means ofconfirming the identity of the amino ester, they are examples of saltsof the amino esters that are within the scope of the invention and thathave particular uses, as for instance use of the picrate as an anionicdye and the hydrochloride and a cationic surfactant.

Example 2Ethyl 2-(MN-Diethylzrminoethyl)acrylate 9.6 g. ethyl2-bromoethylacrylate in 16 g. absolute ethanol were reacted with anethanolic solution of 7.3 g. diethylamine in 4 g. ethanol at atemperature of 10 C. An exothermic reaction occurred and a whiteprecipitate separated.

The reaction mixture was allowed to stand for 19 hrs. in therefrigerator. The amines were then isolated by dissolving the ethanolicsolution and the precipitate in a small amount of water, making italkaline with potassium carbonate, as to pH 10, and extracting the basicmaterial with ether. Evaporation of the dried and filtered etherextracts yielded an oily base. This oily base, ethyl2-(N,N-diethylaminoethyl)acrylate, was distilled in the amount of 4.1 g.(45% theory), B.P. 5556 C. (1.0 mm.), 11 1.4411, (1 0.904.

Infrared absorption spectrum: 1643; 950; 820 cm.* showing The picrate,prepared in ether and recrystallized from ethanol, melted at 9192 C.

Analysis.-Peroent calculated for C H N O C, 46.37; H, 5.35; N, 13.52.Found: C, 46.21; H, 5.27; N, 13.62.

Example 3.Tri-(Ethyl Z-Methylenepropionate) Amine 19.3 g. ethyl2-bromomethylacrylate were dissolved in 40 g. ethanol and reacted slowlywith a solution of 3.3 g. ammonia in 89 g. ethanol at 0-5 C. After 20hrs. at 4, the reaction mixture was acidified with an ether solution ofhydrochloric acid to pH below 7, as to 45, and then evaporated todryness in vacuo. The residue was dissolved in 35 g. water and extractedwith ether after saturation of the aqueous phase with potassiumbicarbonate. The removal of the solvent from the combined ether extractsby evaporation gave 9.2 g. (78% of theory) of a slightly yellow oilwhich could not be distilled in vacuo and which decomposed at atemperature of 200-230 C. The analysis showed that it was tri(ethylZ-methylenepropionate) amine.

A nitrogen determination was made of the crude base obtained.

Analysis.Percent calcd. for C H NO N, 3.96. Found: N, 3.65.

The fact that the reaction product isolated was a tertiary amine wasalso shown by its failure to form a p-nitro-benzoyl derivative whentreated with an equivalent weight of p-nitro-benzoyl chloride inpyridine. In the same manner, treatment of the product with an excess ofacetic anhydride at room temperature for 20 hrs. did not yield an acetylderivative.

Example 4.-Ethyl Z-Aminomethylacrylate The procedure and composition ofExample 1 were followed except that the dimethyl amine there used isreplaced by an equimolar proportion of ammonia. The final product isethyl Z-aminomethylacrylate.

Example 5.--Ethyl 2-(N,N,N-Triethylamm0nium Methyl )Acrylate BromideThere was mixed 10.1 g. triethylamine and a solution of 9.7 g. ethyl2-bromomethylacrylate in 67 g. benzene at room temperature. Anexothermic reaction occurred and a colorless oil separated whichcrystallized into long needles after a few minutes. The reaction mixturewas vigorously shaken from time to time and then stored at roomtemperature for 5 hrs. The precipitate that resulted was filtered anddried under reduced pressure at 20 C., to provide 13.8 g. (96% oftheory) of colorless crystals of ethyl 2-(N,N,N-triethylammonium methylacrylate) bromide of M.P. 97100 C. This quaternary product is verysoluble in water, methanol and acetone and insoluble in less polarsolvents such as ether and petroleum ether. An aqueous solution of thequaternary product with silver nitrate gave an immediate heavyprecipitate of silver bromide. The microanalysis of the product showedits high purity.

Analysis.-Percent calcd. for C H NO Br: C, 48.98; H, 8.22; N, 4.76.Found: C, 49.14; H, 8.48; N, 4.97.

The composition and procedure of this example are used except that thetriethylamine was replaced, in turn, by an equimolar weight of any ofthe other amines disclosed herein for reaction with the2-brornoalkylacrylate ester.

In another modification of this example, the Z-bromoalkylacrylate esteris replaced, in turn, by an equimolar Weight of the correspondingchloroand iodo-esters.

There are thus made a class of quaternary ammonium compounds in which ineffect an alkyl halide is combined with the nitrogen, thus I EN lialogen R' is a (I -C alkyl.

The product is of formula shown earlier herein. It is not only aneffective polyelectrolyte but also an active cationic surfactantsuitable for use as such in detergents and other surface tensionlowering compositions.

Example 6 .The procedure of Example is followed except that thetriethylamine there used is replaced, in turn, by an equimolecularweight of higher homologs such as tripropyl, tributyl, trioctyl or otherC -C alkyl amines. The increased proportion of hydrocarbon component inthe tertiary amine so made gives a product having improved surfaceactive properties adapting it particularly well for use as a detergent.

Example 7 Example 9 The final product of Example 5, namely ethyl2-(N,N,N- triethylammonium methyl)acrylate bromide was polymerized bybeing warmed at 100 C. with 1% of benzoyl peroxide as the initiator ofpolymerization. The polymer so formed is a polyelectrolyte. As such itis useful as a thickening agent and as a brightener in conventionalelectroplating operations. When dissolved in aqueous solvents, thepolyelectrolyte gives solutions of viscosity that is high and can belowered as desired and gradually, by the addition of the bromide ion as,for example, by admixing any alkali metal bromide.

In a modification of this example, the final acrylate products ofExamples 1-4 and 6-8 are used separately and in turn. Each is mixed withan equivalent amount of an aqueous solution of a hydrohalide, examplesof which are hydrochloric and hydrobromic acids, in amount to neutralizethe amino groups in the acrylate used.

The resulting salts are useful as polyelectrolytes in the mannerdescribed.

Example 10.-Use as Ion Exchange Resins The aminoalkylacrylate estersdescribed herein are useful also as ion exchange resins. For thispurpose, the said esters, are adjusted to the alkaline cycle, as bytreatment with a solution of sodium or potassium hydroxide. Thealkalized product is washed with water and brought into contact with anaqueous solution of the anions which are to be exchanged. After thecontact has been maintained for a reasonable period of time, as by slowpercolation of the anions over the alkalized product in granular form,the said anions are exchanged for the anion originally on our alkalizedproduct.

Subsequent separations and restoration of the amino acrylate compound tothe cycle for reuse are efiected in any manner that is conventional inthe art of using ion exchange resins.

Example 1I.Ure as Detergents The ethyl2-(N,N-dimethylaminornethyl)acrylate ester produced in Example 1 isdissolved in water in the proportion of about 0.1% of the ester on theweight of the water, into which water there had been mixed in advance aquantity of a mineral acid equivalent to the amino group or groups inthe arcylate. Examples of such min eral acids that we use arehydrochloric, hydrobromic, sulfuric, and phosphoric acids.

In a modification of this Example, the other aminoalkyl .acrylate estersdisclosed herein, as the final product of Examples 2-8, are separatelysubstituted in equivalent proportion by weight for the said ester. Ineach case the acid forms a salt with the amine group.

These salts, as detergents, may be used alone or may be compounded withphosphates, soap builders, fillers and the like that are usual in suchcompositions as, for instance, with sodium tripolyphosphate or othersodium phosphate and sodium sulfate, in proportions that are usual indetergents.

Another use of the aminoalkyl acrylates of this invention is as basecatalysts, as in curing epoxide resins such as epoxi-dized4,4'-dihydroxyphenylpropane or in accelerating the condensation of suchepoxide compounds with lauryl alcohol, nonylphenyl, or like alcohols andphenols.

It will be understood that it is intended to cover all changes andmodifications of the examples of the invention herein chosen for thepurpose of illustration which do not constitute departures from thespirit and scope of the invention.

We claim:

1. Ethyl Z-aminomethylacrylate.

2. Tri-(ethyl Z-methylenepropionate) amine.

3. Ethyl 2(N,N-dimethylaminoethyl)acrylate.

4. Ethyl 2-(N,N-diethylaminomethyl)acrylate.

5. Ethyl 2-(N,N,N-triethylammoniummethyl)acrylate bromide.

6. The ester of the formula Pelletier et al.: J. Org. Chem. 17, 855-859(1952), cited in Chem. Abs. 47, 1952(1)) 1953.

Chemical Abstracts 52, 11180 (1958).

6. THE ESTER OF THE FORMULA